Those people are idiots and you're doing what you can do with the right tools to make the music happen. I always look at it like this: whoever is paying you is the boss, so you do whatever it takes to make that person happy, and in turn, the people will be happy (idiots and all).
++++1 - what Bo said.
The opinion about there being a problem using a metronome is:
1) ignorant
2) shows inexperience
3) Goes against what many (but not all) pros REALLY use live. Think about all of these R & B acts that have to sync with tracks. Are those drummers weak?
4) Will cause problems if there is any off the cuff remark about a song being too fast or too slow.
Even though a band needs to play together, somebody has to make the decision about what's the best tempo for a song. Then everybody has to go along with that. Then somebody(ies) has/have to be the gate keeper. Otherwise it depends on how different people are feeling that day, what their strengths or weaknesses are at different tempos, if they had a fight with their significant other, etc.
Not saying you can't have someone who gets most of the tempos right but I rarely have come across people that can remember the
exact tempo of a song. It's always a little different. Sometimes that's important and sometimes it's not.
I have a church gig where I have a metronome (The Yamaha Clickstation) mounted off of my hi hat. I'm in charge of counting off most tempos but if I don't, I go with whoever started the song and try to keep it there. Occasionally I'm asked to 'bring us back' to the right tempo. Then they are relying on my inner clock. I work on my inner clock everytime I sit down to play, practicing with a metronome, practicing playing time without it but concentrating on keeping it straight, etc.. Also as mentioned before I'll sing parts of the song to myself. The trick there is singing it at the right tempos in your head!
Another gig I play, I back an actor who's a singer/guitarist. He starts or counts off every song and that's what's right for that song, that night. At that point, it's my job to keep it there. No metronome in sight but my metronomic practice helps to keep us all honest. Not perfect - but as honest as humans can make it.
Bring a metronome. Be VERY able to play the different parts of your bands material at the agreed upon tempos before you get to the practice session or gig. Then use the metronome to either start off the song or keep the headphones/ear buds in place for the duration of the song.
IMHO, this is being responsible about supporting the music. I've heard the sentiment about using a metronome too much and it becoming crutch and to a point I can see it. My experience tells me that most people just don't want to address their own time issues and accuse drummers that play to a click as 'making it sound like a robot'. That can be an issue but most of the times it's not. Ask any prominent session player.
Jim